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T Fujiwara

Publications and source records attributed to T Fujiwara.

At least 901 records · Page 50Linked to original sources
PubMed1990

cDNA cloning and sequencing of component C5 of proteasomes from rat hepatoma cells.

Proteasomes are multicatalytic proteinase complexes consisting of a set of non-identical polypeptide subunits. A cDNA for component C5 of rat proteasomes was isolated by screening a Reuber H4TG hepatoma cell cDNA library using synthetic oligodeoxynucleotide probes corresponding to partial amino acid sequences of the protein. The polypeptide deduced from the open reading frame consisted of 240 amino acid residues with a calculated molecular weight of 26,479. Computer analysis revealed little similarity of C5 to other proteins reported so far. The primary structure of C5 showed partial sequence homology to that of another component C3, but no regions of homology with the sequence of component C2. Thus C5 is concluded to be a new type of subunit of the proteasome complex.

Amino Acid Sequence↗
PubMed1990

Molecular cloning of cDNA for proteasomes from rat liver: primary structure of component C3 with a possible tyrosine phosphorylation site.

Proteasomes are multicatalytic proteinase complexes consisting of multiple components. Previously, we reported the cloning and sequencing of cDNA for the largest component, C2, of rat liver proteasomes [Fujiwara, T., Tanaka, K., Kumatori, A., Shin, S., Yoshimura, T., Ichihara, A., Tokunaga, F., Aruga, R., Iwanaga, S., Kakizuka, A., & Nakanishi, S. (1989) Biochemistry 28, 7332-7340]. In the present study, the nucleotide sequence of another component (C3) of proteasomes has been determined from a recombinant cDNA clone isolated by screening a rat liver cDNA library with synthetic oligodeoxynucleotide probes corresponding to partial amino acid sequences of the protein. The deduced sequence of component C3 consists of 234 amino acid residues with a calculated molecular weight of 25,925. These values are consistent with those obtained by protein chemical analyses. A single mRNA species hybridizing to the C3 cDNA of rat liver was expressed in all rat tissues examined and in a variety of other eukaryotic organisms, its distribution being similar to that of C2 mRNA. The wide distribution of the gene product, possibly C3, suggests that this protein functions similarly in most eukaryotes. C3 is an unmodified protein of a single gene and differs from any other known protein, but its overall amino acid sequence resembles those of other proteasomal components, including C2, suggesting that these components belong to a single family of proteins with the same evolutionary origin.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1990

Brefeldin A arrests the intracellular transport of viral envelope proteins in primary cultured rat hepatocytes and HepG2 cells.

We have studied the effect of brefeldin A (BFA) on the intracellular transport of the envelope proteins of vesicular stomatitis virus (VSV) and sindbis virus in primary cultured rat hepatocytes. BFA (2.5 micrograms/ml) inhibited not only the secretion of plasma proteins into the medium, but also the assembly of both G protein of VSV and E1 and E2 proteins (envelope proteins) of sindbis virus into respective virions. Concomitantly, both the acquisition of endo-beta-N-acetylglucosaminidase H resistance by the G protein and the proteolytic conversion of PE2 to E2 were found to be inhibited in the BFA-treated cells, suggesting that the intracellular transport of the envelope proteins was arrested in the endoplasmic reticulum. Such inhibitory effects of the drug were variable depending upon the culture conditions of the hepatocytes. In the 1-day-cultured cells, even in the presence of the drug, newly synthesized envelope proteins were assembled into the virions after a 3 h chase period, at the same time as secretion of plasma proteins into the medium resumes. In contrast, in 4-day-cultured hepatocytes, BFA continuously blocked the entry of the envelope proteins into the virions and the release of plasma proteins into the medium for at least 5 h. BFA also completely inhibited the exocytotic pathway in HepG2 cells. These results indicate that the duration time of the effect of BFA is different from one cell to another and may change depending upon the culture conditions of the cells.

Animals↗
PubMed1990

Three-dimensional cytoarchitecture of the media of arteriovenous anastomoses in the rabbit ear.

Arteriovenous anastomoses in the rabbit ear were examined with scanning electron microscopy to elucidate the structural differentiation of the media of the shunt. Arterial, intermediate, and venous segments in the shunt and two layers of the media in the intermediate segment were differentiated based on cell shape and cell organization. In the arterial segment, smooth muscle cells were spindle-shaped, either elongated or short, with a few branches, and were arranged circularly or diagonally with respect to the vessel's long axis. There were also stellate muscle cells with radiating processes. In the intermediate segment, the smooth muscle cells of the outer layer of the media were also arranged circularly and resembled the elongated cells in the arterial segments, but they were more irregular in shape and had more processes than those of the arterial segment. The epithelioid cells of the inner layer of the media were oval or polygonal and oriented irregularly with respect to the vessel's long axis, clustering to form longitudinal plicae. The smooth muscle cells of the venous segment were flat with many lateral processes and formed a thin, discontinuous layer. The smooth muscle cells in the arterial segment and those of the outer layer of the intermediate segment exhibited a highly rugged surface texture, indicating their strong contractility; the epithelioid cells and the smooth muscle cells in the venous segment exhibited a generally smooth surface, indicating less contractility. The intermediate segments were supplied with a dense nerve plexus. The intermediate segments, therefore, may be actively involved in the regulation of blood flow under neuronal influence.

Animals↗
PubMed1990

Identification and distribution of atrial natriuretic polypeptide in ventricular myocardium of humans with myocardial infarction.

The expression of atrial natriuretic polypeptide (ANP) in the ventricles of human hearts with myocardial infarction (MI) was studied immunohistochemically. Immunoreactive myocytes were identified in the ventricular tissues of all of 16 hearts with old MI (both with and without heart failure) and in all five hearts with subacute MI, but not in any of the eight hearts without MI nor in the five with acute MI. In the nonfailing hearts with MI, ANP positive myocytes surrounded the areas of infarction, and were also seen in the subendocardium of the infarcted segment. In the failing hearts with MI, ANP expression was noted in the whole ventricular subendocardial region, in addition to the border of infarcts. The sites of ANP expression corresponded well to those of marked stress attributable to tissue shrinkage or fibrosis due to MI, haemodynamic overload, or both. It thus appears that ANP expression is augmented in human hearts with MI regardless of the presence or absence of heart failure, and it is suggested that regional mechanical stress on the ventricular myocardium, as well as haemodynamic overload, may be very closely associated with ventricular ANP expression.

Aged↗
PubMed1990

Antitumor effects of a new interleukin-2 slow delivery system on methylcholanthrene-induced fibrosarcoma in mice.

The interleukin-2 (IL-2) mini-pellet, the carrier material of which is a biocompatible and biodegradable atelocollagen refined from bovine skin, contains 1 x 10(6) units of IL-2 and can release IL-2 slowly in vivo by diffusion and dissolution. We have evaluated the antitumor effects of the IL-2 mini-pellet on an established solid murine tumor, methylcholanthrene-induced fibrosarcoma (Meth A). The subcutaneous administration of the IL-2 mini-pellet alone on days 8 and 11 after tumor inoculation significantly inhibited tumor growth. A significant inhibition was also seen when it was combined with the intravenous injection of 5 x 10(7) lymphokine-activated killer (LAK) cells, in comparison to the untreated controls. Moreover, therapy with the IL-2 mini-pellet alone or in combination with LAK cells also prolonged the survival of mice bearing Meth A fibrosarcoma. In order to determine the precise mechanism of action of these antitumor effects, we tested splenocytes of treated mice for cytotoxic activity in vitro and investigated tumor tissues by an immunohistochemical method. On day 2 after the administration of the IL-2 mini-pellet, the lytic activity of splenocytes against both YAC-1 and JTC-11 cells (i.e. NK and LAK activity) was significantly augmented, and on day 7 a massive accumulation of lymphocytes, which were mainly like Thy1+ and/or asialo-GM1+ LAK cells, was seen in the tumor. These findings indicate that the IL-2 mini-pellet is an appropriate system for local administration of IL-2 and can induce LAK-like effector cells at the target site.

Animals↗
PubMed1990

Clinicopathological study of myocardial infarction with normal or nearly normal extracardiac coronary arteries. Quantitative analysis of contraction band necrosis, coagulation necrosis, hemorrhage, and infarct size.

In order to clarify the pathogenesis of acute myocardial infarction (MI) in hearts with normal coronary arteries, infarct size, and the extent of contraction band necrosis (CBN), coagulation necrosis, and hemorrhage were quantitatively examined using an image analyzer in 5 autopsy cases of MI with normal or nearly normal extracardiac coronary arteries. One patient died 40 h after acute MI. A second patient with acute MI due to severe spasm of segment 6, confirmed by cineangiography, died three days later. The third patient had already suffered a subarachnoid hemorrhage, and died 10 h after the onset of acute MI. The fourth patient had aortic stenosis and regurgitation. She developed acute MI due to total occlusion of segment 6, confirmed by cineangiography 4 h after the onset, and died 61 days later. Autopsy revealed old anteroseptal MI with normal coronary arteries and valvular thrombi. The fifth patient had a malignancy, and died one day after the onset of acute MI. Autopsy revealed multiple occlusive thrombi in the small intramural coronary arteries of the left ventricular wall supplied by segment 14, without any stenosis in the feeding vessel. Most infarcts were localized in the territory supplied by 1 or 2 of the 3 epicardial coronary arteries, and coincided with the clinically diagnosed infarct site. The infarct size ranged from 3%-26% of the left ventricular wall, and infarcts were generally localized to the inner third of the wall (67 +/- 20%). Histological examination of the four patients with acute MI revealed diffuse CBN (86 +/- 14% of the infarcted area) and/or hemorrhage.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Morphometric study of the superior cervical and stellate ganglia of spontaneously hypertensive rats during the prehypertensive stage.

To compare the functional state of the superior cervical (SCG) and stellate sympathetic ganglia (SG) of spontaneously hypertensive rats (SHR) with those of age-matched normotensive Wistar Kyoto rats (WKY), ganglion cell volume and area occupied by ganglion cells relative to each whole ganglionic area were morphometrically examined using the Texture Analyse System (TAS) in rats at 0, 10 and 30 days of age. The weight of each ganglion relative to animal weight was also measured. The ganglion cell volume and the relative area of ganglionic cells in both ganglia of SHR were significantly larger (P less than 0.05) than those of age-matched WKY at ages 0 and 10 days after birth. The relative ganglionic weights of SHR were significantly larger (P less than 0.01) compared with those of WKY at all ages examined, except for SG at 0 days after birth. These results show that the relative volume of sympathetic ganglion cells is greater in both SCG and SG of SHR than that of WKY, suggesting that hyperfunction of sympathetic ganglia occurs at the prehypertensive stage as a primary factor in the development of hypertension in SHR.

Animals↗
PubMed1990

Morphological changes in cerebral vascular smooth muscle cells in stroke-prone spontaneously hypertensive rats (SHRSP). A scanning and transmission electron microscopic study.

The ultrastructure of the vascular smooth muscle cells of the middle cerebral artery in 6-month-old male stroke-prone spontaneously hypertensive rats (SHRSP) was studied by scanning (SEM) and transmission electron microscopy (TEM) and compared with that of age-matched normotensive Wistar Kyoto rats (WKY). Although the smooth muscle cells of WKY rats by SEM had a typical spindle shape and smooth surface texture, those of SHRSP were structurally modified by numerous surface invaginations and projections, bearing some structural resemblance to the myotendinous junction of skeletal muscle. Structural modifications affected more than half the surface of medial smooth muscle cells in SHRSP, but less than 0.6% of the surface of these cells in WKY rats. About 10% of medial smooth muscle cells were necrotic in SHRSP, but no necrotic cells were identified in WKY rats. By TEM, smooth muscle cells in SHRSP were shown to be irregular in profile with deep indentations of the plasma membrane and were surrounded by many layers of basal lamina-like material. The present study suggests that most smooth muscle cells in the middle cerebral artery of SHRSP may be modified to adapt to chronic hypertension by increasing the junctional area between muscle cells and connective tissue and that some cells may undergo necrosis.

Animals↗
PubMed1990

Expression and distribution of atrial natriuretic polypeptide in the ventricles of children with myocarditis and/or myocardial infarction secondary to Kawasaki disease: immunohistochemical study.

We studied the expression and distribution of atrial natriuretic polypeptide in the ventricles of 27 autopsied children with Kawasaki disease. Fourteen of the children had died in the acute stage of the disease. Three without any coronary artery aneurysms died due to myocarditis, while 11 with coronary artery aneurysms also had myocarditis but died of coronary heart disease. Histologic evidence of acute myocardial infarction was noted in three children who died of coronary heart disease. In the 14 children with acute-stage deaths, no abnormal expression of atrial natriuretic polypeptide was noted in the ventricles, despite the presence of heart failure in seven of them for 2 to 22 days before death. The other 13 patients had coronary artery aneurysms and died in the healed stage. In three patients with granulation tissue and congestive heart failure, myocytes in foci around the granulations were moderate to markedly positive for atrial natriuretic polypeptide. These three patients died over 8 days after the onset of their first myocardial infarct. Of 10 patients with old myocardial infarction, four had a history of congestive heart failure. They demonstrated moderate or marked atrial natriuretic polypeptide expression in extensive regions around sites of massive fibrosis, and foci of slight expression in the inner third of the noninfarcted region of the ventricle. In the other six patients without congestive heart failure, there was slight or moderate expression in foci around sites of massive fibrosis. We concluded that the expression of atrial natriuretic polypeptide appeared more than 1 week after the onset of acute myocardial infarction in the ventricles of children with Kawasaki disease who died in the healed stage.(ABSTRACT TRUNCATED AT 250 WORDS)

Atrial Natriuretic Factor↗
PubMed1990

Embryonal carcinoma of the ovary: a six-year survival.

We report a case of embryonal carcinoma, stage II, arising in the right ovary of an 18-year-old woman. The elevated serum levels of alpha-fetoprotein (AFP) and urinary human chorionic gonadotropin (hCG) rapidly normalized after conservative surgery followed by combination chemotherapy. The tumor was composed of large primitive cells and some multinucleated giant cells. AFP and hCG were demonstrated immunohistochemically in each type of cells. She has been disease-free for 6 years.

Adolescent↗
PubMed1990

Clinical assessment of therapeutic effects on cancer using 18F-2-fluoro-2-deoxy-D-glucose and positron emission tomography: preliminary study of lung cancer.

Using positron emission tomography, we studied the tumor uptake of 18F-2-fluoro-2-deoxy-D-glucose (18FDG) in five lung cancer patients before and after anti-cancer therapy (radiotherapy and/or chemotherapy). The tumor uptake of 18FDG was classified as positive and negative; the former, by increasing the uptake of 18FDG with time, and the latter, by decreasing or the constant uptake of 18FDG. Before therapy, all cases tested positive. After therapy, three cases were negative and two cases remained positive. All negative cases corresponded to complete second 18FDG study. Our findings in the 18FDG study correlate with the clinical results. 18FDG is a promising method for assessing therapeutic effects on cancer clinically.

Adult↗
PubMed1990

Bioconversion of 19-deformyl-5-O-desosaminyl tylonolide to 19-deformyl-4'-deoxydesmycosin (TMC-016).

Bioconversion of 19-deformyl-5-O-desosaminyl tylonolide (1) to 19-deformyl-4'-deoxydesmycosin (3) was performed by using a mycinamicin-producing Micromonospora species. Compound 1 at low concentrations was completely converted to compound 3, however, the conversion to compound 3 was suppressed at high concentrations and 19-deformyl-4'-deoxy-2", 3'-di-O-demethyl-desmycosin (2), an intermediate leading to compound 3 accumulated.

Biotransformation↗
PubMed1990

Roles of protein kinase C on the mechanical activity of vascular smooth muscles.

We investigated the role of protein kinase C in the mechanical responses evoked by high K or by acetylcholine (ACh) in intact vascular smooth muscle tissues, and by Ca in skinned vascular smooth muscle tissues. To activate protein kinase C, the phorbol ester 12-o-tetradecanoylphorbol-13-acetate (TPA), a potent tumor promoter, or 1,2-diolein, plus phosphatidylserine (PS) was used. TPA enhanced or reduced the amplitude of the contraction evoked by increased concentrations of K below 39 mmol/L or over 90 mmol/L, respectively, but consistently enhanced the resting tension at any given concentration of high K. Similar effects of TPA were observed on the Ca-induced contraction in saponin skinned muscle tissues. The enhancing action of TPA on the K-induced contraction was not related to activation of either the voltage-dependent Ca channel or the sarcoplasmic reticulum, and did not occur in the case of Ca-independent contraction in skinned muscle tissues. During the enhancement of the contraction induced by TPA, the phosphorylation of myosin light chain and the shortening velocity of contraction as measured using the slack test, were enhanced with no remarkable change in the free Ca concentration in the cytosol. TPA consistently inhibited the ACH-induced contraction accompanied by a marked reduction in free Ca due to inhibition of the hydrolysis of phosphatidyl inositol 4,5-bisphosphate. Under the assumption that TPA possesses the same action as DG, activation of protein kinase C increased the Ca sensitivity of contractile proteins in vascular smooth muscles.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗
PubMed1990

Bacteroides lipopolysaccharides (LPS) induce anaphylactoid and lethal reactions in LPS-responsive and -nonresponsive mice primed with muramyl dipeptide.

Lipopolysaccharides (LPS) (100 micrograms/mouse) from Bacteroides gingivalis elicited anaphylactoid reactions in N-acetylmuramyl-L-alanyl-D-isoglutamine (MDP) (100 micrograms)-primed C3H/HeN mice 0-48 h after MDP injection. The reaction resulted in death within 1 h when the LPS was injected 2-10 h after the MDP injection. LPS prepared from other Bacteroides and Salmonella species but not from others, including Escherichia coli, could induce the reaction. LPS-nonresponsive C3H/HeJ and C57BL/6 and C57BL/10 strains were also responsive to the reaction, while AKR, BALB/c, DBA/2, and ICR mice were not. By contrast, Bacteroides LPS exhibited weak lethal toxicity compared with E. coli LPS in galactosamine-sensitized C3H/HeN mice, while neither LPS had activity in C3H/HeJ mice. LPS from E. coli and Bacteroides intermedius induced serum tumor necrosis factor (TNF) activity in MDP-primed mice, except for C3H/HeJ mice; B. gingivalis LPS rarely induced TNF in C3H/HeN or C3H/HeJ mice, indicating no involvement of TNF in the anaphylactoid reaction. Serotonin could substitute for MDP for the reaction, and methysergide, a serotonin antagonist, inhibited the activity.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1990

A novel aco-type cytochrome-c oxidase from a facultative alkalophilic Bacillus: purification, and some molecular and enzymatic features.

A novel aco-type cytochrome-c oxidase was highly purified from the facultative alkalophilic bacterium, Bacillus YN-2000, grown at pH 10. The enzyme contained 9.0 nmol heme a/mg protein. It contained 1.23 mol of protoheme, 1.06 mol of heme c, 2.0 g atoms of copper, 2.5 g atoms of iron, and 1.8 g atoms of magnesium per mol of heme a. The enzyme molecule seemed to be composed of two subunits with Mrs of 52,000 and 41,600. On the basis of these results, the enzyme seemed to contain one molecule each of heme a, protoheme, and heme c per minimal structural unit (Mr, 93,600). Only protoheme among the three kinds of hemes in the enzyme reacted with CO and CN-. Heme a did not react with CO; cytochrome a3 did not seem to be present in the enzyme. The enzyme oxidized 314 mol of horse ferrocytochrome c per heme a per sec at pH 6.5 and the catalytic activity was 50% inhibited by 7.65 microM KCN. The enzymatic activity was found to be optimal at pH 6.0.

Bacillus↗
PubMed1990

Production of propeptide-directed antibody: its application to the purification of proalbumin and analysis of proalbumin processing.

Antibodies which specifically recognize rat proalbumin, but not mature serum-albumin, were raised. Propeptide (NH2-Arg-Gly-Val-Phe-Arg-Arg) with an additional cysteine residue at the carboxyl terminus was conjugated to ovalbumin through either sulfide or amino group and the conjugates were injected into rabbits. Monospecific antibodies were purified on a propeptide-coupled affinity column and further immobilized as an affinity support, allowing us to purify proalbumin in a single step from rat liver microsomes. The antibodies were also used to analyze the proteolytic processing of proalbumin in primary cultured rat hepatocytes.

Amino Acid Sequence↗